The present invention relates to epitope peptides useful in the specific detection of antibodies against human parvovirus (HPV) B19, an agent for detecting the antibody against human parvovirus B19 which comprises the epitope peptide and a method for detecting the antibody against human parvovirus B19.
Cossart et al. reported that human parvovirus B19 was detected in the human blood (Lancet, 1975, 1, pp. 72-73) and it has been revealed since 1981 that human parvovirus B19 is involved in various human diseases. Human parvovirus B19 is a causal virus of diseases such as erythema infectiosum and arthritis and it has been known that if a pregnant woman is infected with this virus, she suffers from serious diseases such as abortion and hydrops fetalis. For this reason, there has been required for precise and accurate diagnosis of patients. As such diagnostic methods, there have been known, for instance, those which comprise detection of the virus and those which comprise detection of the antibody against the virus. It is inevitable to use a substance serving as an antigen in both of these methods and this is an essential requirement for these diagnostic methods. As such antigens, there have conventionally been used, for instance, human parvovirus B19 derived from human erythroblast cells and a viral antigenic protein prepared according to a genetic engineering technique.
However, antigens derived from human are not easily available and the preparation of such antigenic substances through gene engineering techniques requires the use of complicated operations. Under such circumstances, there has been desired for the development of antigens whose stable supply can be ensured.
In general, it has been believed that an antibody recognizes several amino acid residues of the corresponding antigen and the recognized site of the antigen is called epitope. An antigenic protein has several kinds of epitopes and, therefore, the use of peptides containing these sites permits easy and specific determination or detection of the corresponding antibody without using the virus particles.
The recent progress in the solid phase synthetic technique has permitted relatively easy preparation of various peptides. The sequence of the genomic DNA (gene sequence) of the human parvovirus B19 shown in FIG. 1 was elucidated by Shade et al. (J. Virol., 1986, 58, pp. 921-936). Fridell et al. synthesized peptides corresponding to parts of open reading frame (ORF) 1 and 2 regions on the basis of the foregoing sequence of the genomic DNA and found the reactivity, with the anti-human parvovirus B19 antibody, of peptides having amino acid sequences each corresponding to the sequence extending from 236th amino acid residue to 253th amino acid residue; 284th amino acid residue to 307th amino acid residue and 732th amino acid residue to 741th amino acid residue in the ORF 1 region and the sequence extending from 161th amino acid residue to 170th amino acid residue in the ORF 2 region (Scand. J. Infect. Dis., 1989, 21, pp. 591-603). Moreover, Sato et al. suggested that the peptide having an amino acid sequence corresponding to the sequence extending from 328th amino acid residue to 344th amino acid residue in the viral protein (VP) 2 region can react with the anti-human parvovirus B19 antibody (J. Virol., 1991, 65, pp. 1667-1672).